1. Field of the Invention
This invention relates to a printer connected to an information terminal unit such as a personal computer, an image pickup apparatus, a television receiver or a set top box for printing data transmitted from the information terminal unit, and particularly to a sheet pack removably mounted on the printer and stacking and containing print sheets thereon, and a printer for mounting the sheet pack thereon.
2. Related Background Art
Heretofore, in a printer connected to a personal computer or an image pickup apparatus for printing the data of the personal computer or the image pickup apparatus on a print sheet, a packing bag containing a bundle of print sheets therein has been opened and the print sheets have been set and printed one by one at a sheet feeding port of the printer, or a desired number of print sheets have been stacked and printed on a sheet feeding portion of the printer.
Also, depending on the kinds of the printer, there is one designed such that a sheet stacking and containing device (a so-called sheet cassette) for stacking and containing print sheets thereon is removably mounted on a printer body. When the sheet cassette is to be mounted on the printer body, a user stacks print sheets in the sheet cassette, and thereafter mounts the sheet cassette in a cassette mounting port formed in the printer body.
A design is made such that the print sheets stacked and contained in the sheet cassette are fed into a recording portion in the printer body while being separated one by one by a sheet feeding roller and a separating pad or the like after the sheet cassette has been mounted in the cassette mounting port.
Such a printer according to the earlier technology, however, in any case, has suffered from the problem of being cumbersome in that the packing bag containing the bundle of print sheets therein must be opened and the print sheets must be taken out one by one and set in the sheet feeding port of the printer or a necessary number of print sheets must be taken out of the opened packing bag and be stacked on the sheet feeding portion of the printer.
Also, there has been the problem of cumbersomeness that when the sheet cassette is to be removably mounted on the printer body, the sheet cassette must be once removed from the printer body and the packing bag containing a bundle of print sheets therein must likewise be opened and a necessary number of print sheets must be taken out of the opened packing bag and be stacked in the sheet cassette, which must then be mounted in the cassette mounting port.
Further, when a suitable number of print sheets are contained in the sheet cassette, the number of the print sheets contained in the sheet cassette is unknown to the user and the number of the remaining sheets is also unclear and therefore, there is a case where the print sheets become exhausted in the course of print output. When the print sheets thus become exhausted in the course of print output, the sheet cassette must be removed from the printer body and the packing bag containing a bundle of print sheets therein must be again opened and a necessary or suitable number of print sheets must be taken out of the opened packing bag and be contained in the sheet cassette, whereafter the sheet cassette must be mounted in the cassette mounting port of the printer body and also, an operation for containing the printing must be applied to the printer body or an information terminal apparatus such as a personal computer, and this is very cumbersome.
Also, the printer body and the information terminal apparatus for transmitting data to the printer cannot discriminate between the qualities of paper of the print sheets and therefore, when print sheets unsuitable for the purpose of printing or print data are contained in the sheet pack or are stacked on the print sheet feeding portion or are set in the sheet feeding port, printing is effected on those print sheets, and this leads to the problem that a desired print result is not obtained.
Further, the printer body and the information terminal apparatus for transmitting data to the printer cannot discriminate between the sizes of the print sheets and therefore effects printing on print sheets of a size differing from a desired size, and this also leads to the problem that a desired print result is not obtained.